Abstract: The disclosure relates to condition monitoring of wind turbine pitch bearings by measuring variations in distance between inner and outer rings of a pitch bearing during an angular rotation. Example embodiments include a method of monitoring a condition of a pitch bearing (100) of a wind turbine, the pitch bearing comprising a first ring (102) attached to a blade of the wind turbine and a second ring (103) attached to a hub of the wind turbine, the method comprising: mounting a displacement sensor (105) to the pitch bearing (100) to measure a distance between the first ring (102) and the second ring (103); rotating the first ring (102) relative to the second ring (103) over an angular range; and recording an angular position (204) of the first ring (102) relative to the second ring (103) and a distance (205a, 205b) measured by the displacement sensor (105) while rotating the first ring (103) relative to the second ring (103) over the angular range.

Abstract: A power device includes a motor, a drive shaft, and a roller brake system including a cam mechanism. The motor may put out a driving torque in a first and a second rotary direction. The cam mechanism includes first and second cam members. The first cam member may be in a driven engagement with the motor and the second cam member may be slidably engaged with the first cam member and coupled to the drive shaft. The first cam member includes a circumferentially disposed ramped surface having a stop member at a first end thereof. The said second cam member is axially and rotatably fixed with the drive shaft and includes an axially extending protrusion disposed about a circumference thereof and slidably engaged with the ramped surface.

Abstract: A brake mechanism having a motor output shaft outputting a driving torque in a power-in and a power-out direction. A camming device operably couples the output shaft to a drive shaft for fixed rotation. A one-way clutch operably couples the drive shaft and a brake device. The brake device is normally in an engaged position that prevents rotation of the clutch device. During a holding maneuver, the one-way clutch, camming device, and brake device cooperate to prevent uncommanded movement. However, the nature of the one-way clutch permits free rotation during a power-in direction and the nature of the camming device permits free rotation during a power-out direction.

Abstract: An object management system for storing persistent object oriented objects, includes an object vault, a structural type manager and a digital library. The object vault is connected to the structural type manager and the digital library is connected to the structural type manager. An application program is connected to the object vault. Objects to be stored are represented as a Key Value Dictionary (KVD) in which attributes, or metadata, relating to the objects are stored as key-value pairs. Objects are categorized as having different structural types in which certain attributes for objects having the same structural type are cataloged to facilitate indexing and searching for the objects. The structural type manager maintains a mapping between structural types and a subset of keys for the structural types as well as corresponding database references for cataloging the object attributes.

Abstract: The present invention is directed to a method and apparatus for supporting large digital objects. More particularly it relates to a client/server library system in which a large digital object is divided into smaller pieces which are stored in the client/server library system. By dividing the large digital object into smaller pieces, system limitations regarding object size are avoided. In one embodiment of the present invention the pieces are stored as files of variable size. Moreover, the pieces can be stored on separate object servers which can be located remotely from one another.